CTD data collected about the equator along 85¿W between October 8 and 12, 1982, are used to investigate stratification changes in the upper 1 km associated with the 1982/83 El Ni¿o. With respect to the thermal field observed in November 1981, virtually the entire section exhibited downward displacements in the upper kilometer of the water column. Observed displacements at the depth of the mean thermocline were large (~150 m) and relatively symmetric about the equator. Displacements around 1 km depth were near zero. This stratification change appears to have been produced by a zonal convergence of mass at temperatures about 15¿C, with divergence below. Least square modal decompositions of the vertical displaced profiles revealed significant contributions from modes 1 and 2 with meridional structure consistent with Kelvin waves. The observations thus support current theories that relate El Ni¿o onset in the eastern Pacific to anomalous wind forcing in the west.